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2 sheets-sheet `1 R. B. KNOTH AIR OPERATED PUNCH PRESS GUARD Nov. 22, 1955 Filed Nov. 8, 1952 /A/ I/E N 7' 01? f?. 6i /f/vo TH A rick/wv Nov. 22, 1955 R. B. KNOTH 2,724,287

AIR OPERATED PUNCH PRESS GUARD Filed Nov. 8, 1952 2 Sheets-Sheet 2 A TTORIVEY United States Patent O1 AIR OPERATED `PUNCH PRESS GUARD Richard B. Knoth, Oak Park, Ill., assigner to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application November 8, 1952, Serial No. 319,511

7 claims. (C1. Pltr- 616) 'I'his invention relates to safety guards for punch presses and more particularly to an air operated mechanism for actuating a safety guard on a punch press.

An object of the present invention is to provide an improved mechanism for actuating a safety guard on a punch press.

A further object of the invention is to provide a mechanism for controlling the actuation of a safety guard on a punch press to insure the movement of the guard to its operative position prior to the movement of the ram of the press.

`In accordance with one embodiment of the invention as applied to a punch press having a reciprocable ram, a foot treadle for controlling the actuation of the ram,

an extensible and retractible safety guard, and an air operated actuator for the guard, there is provided an air operated control valve which has a movable valve element operable in a normal rst position to direct air from a source of compressed air to one end of the actuator to eifect the retraction of the safety guard `and operable in a second position for directing compressed air into the opposite end of the actuator to `extend the safety guard into operative position. The movable valve element, which is spring actuated to its normal position, has an air operated actuator associated therewith for moving the valve element to its second position in response to the flow of air into the actuator under control of a first valve actuated by the treadle rand a second valve actuated by the ram, the rst and the second valves serving to insure that the guardis in extended position at all times except when both the ram and the treadle are in their normal inoperative positions.

Other objects and advantages of the invention will become apparent by reference to the following detailed description and the accompanying drawings, in which Fig. l is a somewhat diagrammatic front elevational view of a punch press having a movable safety guard thereon and the improved mechanism for actuating said guard; p

Fig. 2 is an enlarged elevational view of the safety guard in extended position; and

Fig. 3 is a diagrammatic view of the mechanism for actuating the safety guard. Referring to the drawings, in Fig. 1 there is shown a punch press having a reciprocable ram 11 for carrying movable `tools 12 which cooperate with stationary tools 13 mounted on the bolster plate 14 of the press. The ram 11 is pivotally connected to a rod 17 which is reciprocated by an eccentric 18 on a shaft 19, which in turn is rotated by a suitable motor drive (not shown) and a one-revolution clutch (not shown) under control of a foot treadle 20. `The foot treadle 20, which is mounted for pivotal movement about theaxis 23, is urged upwardly by a spring 24 to its normal upper position and in response to the downward movement thereof the treadle through elements connected thereto effects the engagement of the one-revolution clutch and the reciprocation of the ram 11.

`lf the operator is slow in releasing the treadlefrom its Acn "ice

depressed position, the one-revolutiomclutch may be reengaged for a second cycle and the ram 11 may be actuated through a second reciprocation. For a single operation of the ram 11 the operator depresses the treadle 20 and immediately releases it, and for continuous operation of the ram 11 the operator depresses the treadle 20 and retains the treadle in depressed position for the length of time it is desired to have the ram reciprocate.

A movable safety guard 30 is provided for movement from a normally retracted position as shown in Fig. 1 to anextended position as shown in Fig. 2 in front of the ram 11 and the dies 12 and 13 to protect the operator from injury. The safety guard may be of any suitable type capabile of movement to an extended position between the operator and the dies and a retracted position to permit access to the dies of the press.

As shown herein the safety guard comprises a plurality of pairs of bars 34-34 pivotally connected to each other at their ends by pins 35 and 36 and pivotally connected to each other intermediate their ends by pins 37. One end of one end bar 34 is mounted for pivotal movement about a fixed pivot 40 on a bracket 41 which is mounted on the bolster plate 14 of the press and the free end of the other end bar 34 has a roller 42 connected thereto which is guided for vertical movement in a guide 43 in the bracket 41. The pins 35 have portions thereof supported for horizontal movement in a guideway 44 of a guide bar 45 fixed to the upper end of the bracket 41. A plurality of movable guard plates 46 are connected at their upper ends to the pins 35 and are provided with slots 47 for receiving the pins 36 therein. The plates 46 are offset relative to each other so that they may be moved horizontally to and from the extended position shown in Fig. 2 and the retracted position shown in Fig. l in which position the plates are nested together.

The guard 30 is moved to and from its extended and retracted positions by a iluid actuator 55 comprising a cylinder 66 supported on the bracket 41 and a piston 67 reciprocable within the cylinder. A piston. rod 68 of the piston 67 is connected to one arm of a bell crank 69 which is mounted for oscillating movement about a fixed pivot support 70 and has its other arm connected to one end of a link 71, the other end of which is connected to the pin 37 of the first pair of bars 34.

A pair of conduits 74 and 75 connect the opposite ends of the cylinder 66 to a pair of outlet ports 76 and 77 in the housing or body portion 78 of a uid actuated control valve 80 which is suitably supported on the frame of the punch press 10. An intake port 31 in the body member of the control valve 80 is connected to a conduit 82 for supplying air under a predetermined pressure from a suitable source of supply to the valve 80. A movable valve member of the piston type is mounted for reciprocation within the valve body 78, and the valve body 78 and the valve member 85 Aare so arranged that when the valve member 85 is in its normal position as shown in Fig. 3, air is directed from the intake port 81 through the outlet port 76 to` the upper end of the actuator 55 for moving the guard to its retracted position.

The valve member 85 has a piston 87 secured thereto which is mounted for reciprocation within a cylinder 83 of a iiuid actuator mounted on the valve body 78. A spring 91 within the cylinder 88 moves the piston 37 and the valve member 85 in one direction to a normal position and yieldably retains it in said position. Conduit means including the line 93 and branch lines 94 and 95 are connected to the conduit 82 for supplying compressed air to the actuator 90 for actuating the piston S7 in the valve 85 to a second position for directing air from the intake port 81 through the outlet port 77 to the lower end of the actuator 55 for effecting the movement of the guard to its extended position.

'In 'the branch conduits 94 and 95 there are provided valves 98 and 99 having movable valve members 100 and 101 therein which are movable to and from open and closed positions to permit or shut off the ow of air therethrough. The normally open valve 99 is mounted on the press adjacent the treadle 20 and is arranged relative thereto so that the treadle engages the movable valve member 1'01 and vmoves it to its closed position in response 'to the final portion of the movement of the treadle to its upper or inoperative position. 1n response to the initial downward movement of the treadle Zi to its operative position for effecting the actuation of the ram 11, the

. valveV member 99 is caused to move to its open position and allow compressed `air 'from the conduit 32 to flow through the valve 99 into the fluid actuator 90 to move the valve member 85 to its 'second position and thereby to cause the flow of compressed air into the lower end of the 'actuator 55 for 'effecting the movement of the guard 30 to its extended position. Upon the return of the treadle 20 to its normal upper inoperative position the valve member 101 is moved thereby to its closed position to shut off the supply of air to the actuator 90.

An exhaust valve 164 having a bleed port 105 of a predetermined size is vconnected in the line 93 for exhausting the air trapped in the cylinder 83 to permit the spring 91' to return the piston 87 in the valve member 85 to its normal position. The valve 104 is designed to maintain a predetermined air pressure in the line 93 while exhausting a portion of the air therefrom when either of the valves 98 or 99 are open and to quickly bleed off the air from the cylinder 88 of the actuator 90 when the air pressure to the actuator has been shut off by the valves 93 and 99.

The valve 98 is suitably mounted on the frame of the punch press with the movable valve member 100 inA close proximity to a vertical side of the ram 11 and at the lower portion thereof. A cam 107 is mounted on the ram 11 with the lower inclined portion thereof in close proximity to the movable member 100 of the normally closed valve 9S when the ram 11 is in its upper or inoperative position. In response to the downward movement of the ram 11, the cam 107 actuates the Inovable valve member 109 to itsopen position permitting the compressed air from the conduit 82 to flow through the valve 98 into the line 93 and into the actuator 90 to move the valve member '55 to its second position and thereby effect the actuation of the guard 30 to its extended position.

The valves 9S and 99 are arranged relative to the ram 11 and the treadle 20 so that they cooperate to connect the air actuated control valve 8f) with the air line 82 in response to movement of either the treadle or the ram 11 from their normal upper inoperative positions to actuate the control valve 80 to its second position and effect the actuation of the guard 30 to its extended position. Thus, this mechanism insures that the guard 30 is actuated to its extended position at all times during the movement of either the ram and the treadle except when both the ram and the treadle are in their upper inoperative position and that the guard is moved to its extended position prior to the movement of the ram.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

l. A fluid operated mechanism for actuating a movable safety guard on a punch press having a reciprocable ram and a treadle for effecting the operation of said ram, said mechanism comprisinga first fluid actuator for moving said` guard to and from retracted and extended positions, means including a control valve interconnecting a .source of fluid under pressure and V theopposite ends of said first actuator, resilient means for actuating said control valve to a first position -for directing fluid into one end of said first actuator to effect the movement of said guard to said retracted position, a second fluid actuator operable to move said control valve to a second position to direct fluid into the other end of said first actuator to effect the movement of said guard to its extended position, and means including first and second shut-off valves interconnecting said second actuator and said source of fiuid, said first and said second shut-off valvesbeing movable from normally closed to open positions to effect the actuation of said control valve to said second yposition in response to the movement of said ram and said treadle, respectively, from their normal inoperative positions.

2. A fluid operated mechanism for actuating a movable safety guard on a punch press having a reciprocable ram and a treadle for effecting the operation of said ram, said mechanism comprising a cylinder and piston operatively connected to said guard for moving it lto and from retracted and extended positions, conduit means including a control valve interconnecting a source `of fiuid under pressure and the opposite ends of said cylinder, said control valve being urged to a normal first position and operable in said first position to direct fluid into one end 'of said cylinder to effect the movement of the 'guardto said retracted position and operable in a second position to direct fluid into the other end of the cylinder to effect the movement of the guard to its extended position, a fiuid actuator operable to move said control valve to saidy second position, and means including a pair of shut-off valves interconnecting said fluid actuator and said source of uid, one of said shut-off valves being actuated to and from open and closed positions by the movement of said ram to supply fiuid to effect the actuation ofl said control valve to said second position in response to movement of said ram from its upper position, the other of said shut-off valves being operable to and from closed and open positions by the movement of said treadle to supply fluid to said fluid actuator and effect the actuation of said control valve to said second position in response to the movement of said treadle from its upper inoperative position.v

3. A mechanism for actuating a movable safety guard on a punch press having a reciprocable ram and a treadle for effecting the operation of said ram, said mechanism comprising means including a piston and cylinder for actuating said movable safety guard to and from retracted and extended positions, a control valve having a movable valve member operable in a first position for directing fiuid from a source of fluid under pressure into one end of said cylinder to effect the `movement of said safety guard to said retracted position, means for moving said movable member to said first position,` a fluid actuator operable infresponse to the admission of fiuid into one end thereof to move said movable valve member to a second position for directing fluid from said source into the other end of said cylinder to effect the movement of said guard to said extended position, and means including a pair of shut-off valves interconnecting one end of said fluid actuator and said source of fluid, one of said shut-off valves having a closed position when said ram is in its normal upper position and being operable to an open position in response to movement of said ram from said upper position, the other of said shut-off valves having a closed position when said treadle is in its normal inoperative position and being operable to an open position in response to movement of said treadle from said inoperative position.

4. A fluid operated mechanism for actuating a movable safety guard on a punch press having a reciprocable ram and a treadle for effecting the operation of said ram, said mechanism comprising a first liuid actuator for actuating said guard to and from retracted and extended positions, conduit means interconnecting a source of fluid under pressure and the opposite ends of said iiuid actuator, a control, .valve in said conduit means operable in a first said fiuid actuator andk position to direct fluid into one end of said fluid actuator to effect the movement of said guard to said retracted position and operable in a second position to direct fluid into the other end of said fluid actuator to effect the movement of said guard to its extended position, resilient means for actuating said control valve to said first position, a second fluid actuator operable to actuate said control valve to its second position in response to the admission of fluid to one end thereof, conduit means including a pair of shut-off valves interconnecting said one end of the second fluid actuator and said source of fluid, one of said shut-off valves being actuated to and from open and closed positions in response to the movement of said ram to direct iiuid to said second actuator in response to movement of said ram from its upper position, the other of said shut-off valves being operable to and from closed and open positions in response to the movement of said treadle to direct uid to said second actuator in response to movement of said treadle from its upper inoperative position, and means for releasing fluid from said one end of the second fluid actuator.

5. The combination with a punch press having a reciprocable ram, a treadle movable from an inoperative position to an operative position to effect the reciprocation of said ram, and a safety guard movable to and from retracted and extended positions, of a first fluid actuator for moving said safety guard to said extended position in response to the admission of fluid into one end thereof, a control valve for controlling the flow of said fluid from a source of supply into said one end of the actuator, a movable valve element in said control valve stressed for movement to a normal first position for shutting off the flow of fluid from said source of supply to said one end of the first actuator, a second fluid actuator for moving said valve member to a second position in response to the admission of fluid into one end thereof for establishing the flow of said fluid to said one end of the first actuator for effecting the movement of the safety guard to its extended position, means for returning said guard from said extended position to said retracted position, means including a pair of shut-off valves for directing uid from said source of supply to said one end of the second fluid actuator, one of said shut-off valves being actuated by said ram from a closed position when said4 ram is in its normal upper position to an open position in response to movement of said ram from said upper position, the other of said shut-off valves being actuated by said treadle from a closed position when said treadle is in its normal upper position to an open position in response to the movement of said treadle from said upper position, and means communicating with said one end of the second fluid actuator for bleeding the fluid therefrom.

6. A mechanism for controlling the operation of a movable safety guard on a punch press having a reciprocable ram and a treadle for effecting the operation of said ram, said mechanism comprising means including a piston and cylinder for actuating said movable safety guard to and from retracted and extended positions, a.

control valve comprising a valve body and a movable member, said body having an intake port and a pair of outlet ports, conduit means interconnecting said intake port and a source of compressed air, conduit means interconnecting the outlet ports and opposite ends of said cylinder, resilient means for moving said movable valve member to a normal first position for directing the air from said intake port through one of said outlet ports into one end of said cylinder to effect the movement of said safety guard to said retracted position, a fluid actuator operable in response to the admission of compressed air thereinto for moving said movable valve member to` a second position to direct air from said intake port into the other end of said cylinder to effect the movement of said guard to said extended position, and means including a pair of shut-off valves interconnecting said fiuid actuator and said source of compressed air, one of said shut-off valves having a closed position when said ram is in its normal upper position and being operable to an open position in response to movement of said ram from said upper position, the other of said shut-off valves having a closed position when said treadle is in its normal inoperative position and being operable to an open position in response to movement of said treadle from said inoperative position.

7. A uid operated mechanism for actuating a movable safety guard on a machine having a reciprocable ram and a manually operated element for effecting the operation of said ram, said element having a normal inoperative position, said mechanism comprising a cylinder and piston operatively connected to said guard for moving it to and from retracted and extended positions, conduit means including a control valve interconnecting a source of fluid under pressure and the opposite ends of said cylinder, means for urging said control valve to a normal first position, said control valve being operable in said first position to direct uid into one end of said cylinder to effect the movement of the guard to said retracted position and operable in a second position to direct uid into the other end of the cylinder to effect the movement of the guard to its extended position, a fiuid actuator operable to move said control valve to said second position, and means including a pair of shut-off valves interconnecting said Huid actuator and said source of fluid, one of said shut-off valves being actuated to and from open and closed positions by the movement of said ram to supply fluid to said fluid actuator and effect the actuation of said control valve to said second position in response to movement of said ram from its upper position, the other of said shut-ofi:` valves being operable to and from closed and open positions by the movement of said manually operated element to supply fluid to said uid actuator and effect the actuation of said control valve to said second position in response to the movement of said element from its normal inoperative position.

No references cited. 

